Welding operations generally involve providing a welding arc between a welding electrode and a workpiece being welded, where the arc operates to melt the electrode material for deposition onto the workpiece to create a weld joint. Modem welding systems include a power source and a wire feeder, as well as a supply of welding electrode wire (typically on a spool) and may also include an optional supply of shielding gas. The electrode, sometimes referred to as a welding wire, is fed through a torch cable to a welding torch or gun, and electrical power is provided to the torch via electrical wiring in the torch cable. A conductive contact in the welding torch applies the welding power to the electrode for establishing an arc between the exposed portion of the electrode and the workpiece. If external shielding gas is used, for example, in gas metal arc welding (GMAW) processes, the torch cable also includes passageways for providing pressurized gas to shield the welding arc and weld metal from ambient conditions. The wire feeder includes one or more motorized rollers that direct the welding electrode from a supply reel through a tube in the torch cable, where the wire feeding apparatus may be included within the power source enclosure or may be separately housed.
Portable wire feeders are often used in shipyards and other situations where the location of the welding operation changes from time to time and is remote from the power source. This might include, for example, welding operations at job sites that change day-to-day or welding operations that cover a large area at a single job site. In these devices, a power source cable (sometimes referred to as an electrode cable) provides electrical power from the power source to the remote wire feeder. The portable wire feeder is connected to the welding torch by a torch cable having electrical wiring for providing power from the power source to the torch, as well as an internal tube for transporting the wire electrode, where the torch cable may have further optional provisions (e.g., passageways) for providing shielding gas to the torch and/or for circulating cooling fluid through the torch. In this manner, the remote wire feeder can be easily relocated to particular welding cites without moving the power source. In a typical arrangement, the portable wire feeder includes a housing or enclosure with an input cable for connecting to the power source cable to receive the welding power from the power source, as well as an output connected to a torch cable to which the welding power is provided together with the welding wire driven by a motorized wire feeding mechanism. Matiash U.S. Pat. No. 6,707,004, incorporated herein by reference, describes a wire drive assembly having a cable securing built in to a wire drive casting for use in bench or stationary wire feeders where the electrode power is turned on and off directly at the power source. However, portable wire feeders typically have a means for switching the arc current, such as a contactor. In this regard, portable wire feeders are generally powered by the arc current, where power received from the power source cable at a wire feeder input is used to drive a wire feed control motor that rotates feed rolls for pulling wire from the spool or reel and forcing it through the gun or torch cable. A trigger on the torch closes a switch to initiate the welding operation (provision of electrical power to the welding electrode in the torch) as well as to start the drive motor for feeding wire. Examples of such remote or portable wire feeders include model numbers LN-25 and LN-15 sold by The Lincoln Electric Company of Cleveland, Ohio.
In operation, an electrical contactor is provided in the portable wire feeder housing and is controlled by the torch trigger to direct welding current to the torch contact surrounding the advancing wire electrode. Thus, whereas stationary wire feeders provide no internal power switching, portable wire feeders typically include on-board power switching apparatus. Furthermore, because the power source is often remote from the welding operation, operator controls and other user interface elements are sometimes provided on the portable wire feeder, for instance, allowing adjustment of welding current, wire feed speed, etc. Despite these differences, it is of course desirable for portable wire feeders to operate generally in the same manner as conventional stationary wire feeders with respect to controlling applied welding current and wire feed speed. However, such portable feeders are subjected to repeated movement and use in connection with a wide range of work environments, many of which can be severe, whereas stationary wire feeders typically enjoy controlled and unchanging environments, such as a work shop or factory floor. In addition to functioning like a stationary wire feeder, the portable wire feeder is preferably compact and lightweight enabling it to be more easily moved and used in confined work areas, as well as rugged and durable to withstand frequent transport and/or use in adverse conditions.
Referring to FIGS. 1A and 1B, because portable feeders are relocated frequently and are often used outdoors long distances away from the welding power source or maintenance offices, it is desirable to make the connection of the power source cable to the wire feeder input be simple, rugged and serviceable with a minimal number of tools. FIGS. 1A and 1B illustrate welding systems 2a and 2b with portable wire feeders 4a and 4b for providing power and welding wire from supply reels 3a and 3b to welding torches or guns 8a and 8b, respectively, showing different conventional methods of connecting power from a power source 6 to the remote wire feeder 4. FIG. 1A shows the system 2a including a welding power source 6a that provides electrical power to the wire feeder 4a by means of a power source cable 10a. In this approach, lugs 12 are attached to the ends of the cable 10a, and one end is connected to a lug bolt 7 at the output of the power source 6a using a threaded nut 5. The lugged cable 10a is then attached directly to a stud or bolt (not shown) inside the wire feeder 4a, or a short cable 14 is provided extending from the wire feeder 4a, which also includes a lug 12, as shown in FIG. 1A. In this case, the power source cable 10a and feeder cable 14 are bolted together at the lugs 12 using a bolt 9 and a nut 5, after which and the connection is insulated with insulating tape (not shown). A disadvantage to the lugged connection of FIG. 1A is that tools and tape are required for connecting the cable 10a to the wire feeder 4a. If one of the cables 10a, 14 breaks, moreover, it is necessary to put a new lug on the end of the cable, resulting in lost time while the parts and tools are found to make the repair.
FIG. 1B illustrates another conventional approach in the system 2b, where a cable 10b is provided for connecting power source 6b with the wire feeder 4b. The power source cable 10b in this case includes special “quick connects” 20 and 22 for attaching the cable 10 to the feeder 4b via a short feeder cable 24. The interconnection of the system 2b provides a specially machined female connector 22 attached to the feeder end of the cable 10b, and a mating male connector 20 attached to the wire feeder cable 24. Examples of these interconnections include connectors of model numbers K852-70 and K852-95 sold by The Lincoln Electric Company. These connectors 20 and 22 can be assembled and disassembled without tools or tape, thereby providing certain advantages over lugged connections of FIG. 1A, in that they are typically repairable without special lugging tools. However, the quick connects 20 and 22 are typically relatively large and prone to breaking. Furthermore, different types of quick connectors are providing by competing suppliers that are generally not interchangeable, wherein no single design has become an industry standard. Consequently, as the equipment is moved from job site to job site, the connectors need to be constantly changed. Thus, there is a need for improved portable wire feeders and connection apparatus therefor to facilitate connection of a power source to a remote portable welding wire feeder that is easily serviceable without specialized tooling.